This is my first post in this forum. I am a beginner since Jan this year.
I would need a BIG favor from this forum to see how to save my BACK, which opened 3cm from bottom, 5cm from top while I was graduating last night. I believe that I did not have enough glue when I rubbed-joint few weeks ago. I am loacted in Southern California, so I do not think it is weather issue at all, the weather here is so perfect.
I really do not know what to proceed to rescue this.
Please help!!!

Hello Tsenglo, can you post us some photos of the damage?
what kind of glue have you used?
Where do you live in California? The weather in California is perfect for the violins and the violinmaking, better than Italy (too much humdity).

Hi Caludio,
I am in Los Angeles area. The weather is very good for violin making I guess. I am sorry that I do not have the pictures on hand now. I was so upset last night, I simply walked away for a night after I saw the disaster. I will post it after work.

Probably it was a bad glueing procedure, so I think of a probable weakness of your maple back. Be careful, a bad glueing will give you bad conseguences in the future. You can completely reopen your back (and repair it) or start with a new one.

I resume briefly a correct procedure to prepare a good hide glue:
1 part hide glue, 2 (or 3) parts water. Warm up at about 60/70°C. Then apply it to both surfaces and rub it for about 20 seconds, then let dry. I use the rub joint commonly and never had a problem. It's important that you have perfect surfaces, work with a well sharpened plane. Don't use the sandpaper to plane the surfaces to join.

I thought I spent quite a time to plane the back, presumably it was perfect surface because I could kind of feeling the suction in barewood rubbing. So I think it is NOT enough glue in this case. I have very good LN jack plane and good quality og hide glue.

I wish I could save the back or I will restart it on weekend. Unfortunately my Ciresa wood could only be used after Xmas.

Yes, per Frank's suggestion, I procured all the professional tools even I do not know how may violin I could make. I even recently bought a carving board identical as your fr0m Bogaro & Clemente, though it is not essential to be a good maker, but the good euqipment do save me time and I could enjoy the making more.